1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _ASM_X86_PGTABLE_32_H
3#define _ASM_X86_PGTABLE_32_H
4
5#include <asm/pgtable_32_types.h>
6
7/*
8 * The Linux memory management assumes a three-level page table setup. On
9 * the i386, we use that, but "fold" the mid level into the top-level page
10 * table, so that we physically have the same two-level page table as the
11 * i386 mmu expects.
12 *
13 * This file contains the functions and defines necessary to modify and use
14 * the i386 page table tree.
15 */
16#ifndef __ASSEMBLY__
17#include <asm/processor.h>
18#include <linux/threads.h>
19#include <asm/paravirt.h>
20
21#include <linux/bitops.h>
22#include <linux/list.h>
23#include <linux/spinlock.h>
24
25struct mm_struct;
26struct vm_area_struct;
27
28extern pgd_t swapper_pg_dir[1024];
29extern pgd_t initial_page_table[1024];
30extern pmd_t initial_pg_pmd[];
31
32void paging_init(void);
33void sync_initial_page_table(void);
34
35#ifdef CONFIG_X86_PAE
36# include <asm/pgtable-3level.h>
37#else
38# include <asm/pgtable-2level.h>
39#endif
40
41/* Clear a kernel PTE and flush it from the TLB */
42#define kpte_clear_flush(ptep, vaddr)		\
43do {						\
44	pte_clear(&init_mm, (vaddr), (ptep));	\
45	flush_tlb_one_kernel((vaddr));		\
46} while (0)
47
48#endif /* !__ASSEMBLY__ */
49
50/*
51 * kern_addr_valid() is (1) for FLATMEM and (0) for SPARSEMEM
52 */
53#ifdef CONFIG_FLATMEM
54#define kern_addr_valid(addr)	(1)
55#else
56#define kern_addr_valid(kaddr)	(0)
57#endif
58
59/*
60 * This is how much memory in addition to the memory covered up to
61 * and including _end we need mapped initially.
62 * We need:
63 *     (KERNEL_IMAGE_SIZE/4096) / 1024 pages (worst case, non PAE)
64 *     (KERNEL_IMAGE_SIZE/4096) / 512 + 4 pages (worst case for PAE)
65 *
66 * Modulo rounding, each megabyte assigned here requires a kilobyte of
67 * memory, which is currently unreclaimed.
68 *
69 * This should be a multiple of a page.
70 *
71 * KERNEL_IMAGE_SIZE should be greater than pa(_end)
72 * and small than max_low_pfn, otherwise will waste some page table entries
73 */
74#if PTRS_PER_PMD > 1
75#define PAGE_TABLE_SIZE(pages) (((pages) / PTRS_PER_PMD) + PTRS_PER_PGD)
76#else
77#define PAGE_TABLE_SIZE(pages) ((pages) / PTRS_PER_PGD)
78#endif
79
80/*
81 * Number of possible pages in the lowmem region.
82 *
83 * We shift 2 by 31 instead of 1 by 32 to the left in order to avoid a
84 * gas warning about overflowing shift count when gas has been compiled
85 * with only a host target support using a 32-bit type for internal
86 * representation.
87 */
88#define LOWMEM_PAGES ((((_ULL(2)<<31) - __PAGE_OFFSET) >> PAGE_SHIFT))
89
90#endif /* _ASM_X86_PGTABLE_32_H */
91